Electronic device

ABSTRACT

An electronic device includes: a plurality of oscillators ( 10 ) that output modulation waves of a parametric speaker; a display unit ( 40 ) that displays a plurality of contents at the same time; a recognition unit that recognizes the locations of a plurality of users; and a control unit that controls the oscillators ( 10 ) so as to reproduce sounds corresponding to the contents. The control unit controls the oscillators ( 10 ) so as to reproduce the sound corresponding to the content selected by each user, toward the location of each of the plurality of users which is recognized by the recognition unit.

TECHNICAL FIELD

The present invention relates to an electronic device using ultrasonicwaves.

BACKGROUND ART

Various studies on a technique regarding an electronic device such as aportable terminal device have been conducted. For example, PatentDocument 1 discloses a technique in which a distance between an antennamounted in a portable communication device and a head is measured usingultrasonic waves and matching conditions of a matching circuit of thecommunication device are changed on the basis of the distance. Inaddition, Patent Documents 2 to 4 disclose a technique regarding aspeaker of a portable terminal device.

Patent Document 2 discloses a technique in which a distance from anobject imaged by an imaging unit is measured and a sound is constantlylocated in a predetermined space depending on the distance. In addition,Patent Document 3 discloses a technique in which a distance between anauditor and a speaker is measured and the distance is reflected in acoefficient of a filter using a head-related transfer function (HRTF)modeled as a database. Further, Patent Document 4 discloses a techniqueregarding a portable terminal device including a plurality ofsuperdirective speakers that output sound signals.

RELATED DOCUMENT Patent Document

[Patent Document 1] Japanese Unexamined Patent Publication No.2000-124723

[Patent Document 2] Japanese Unexamined Patent Publication No.2006-157558

[Patent Document 3] Japanese Unexamined Patent Publication No.2007-28134

[Patent Document 4] Japanese Unexamined Patent Publication No.2006-67386

DISCLOSURE OF THE INVENTION

In an electronic device that displays a plurality of contents at thesame time, when a plurality of sounds corresponding to each content arereproduced, these sounds are mixed together. For this reason, when aplurality of users view different contents, it is difficult for the userto recognize the sound corresponding to the content that he or she isviewing. Accordingly, in an electronic device that displays a pluralityof contents at the same time, when a plurality of users view differentcontents, it is required for a sound corresponding to the contentselected by each user to be capable of being reproduced with respect tothe user.

An object of the present invention is to provide an electronic devicethat displays a plurality of contents at the same time, wherein a soundcorresponding to the content selected by each user is reproduced withrespect to the user.

According to the invention, there is provided an electronic deviceincluding: a plurality of oscillators that output modulation waves of aparametric speaker; a display unit that displays a plurality of contentsat the same time; a recognition unit that recognizes the positions of aplurality of users; and a control unit that controls the oscillators soas to reproduce sounds corresponding to the contents, wherein thecontrol unit controls the oscillators so as to reproduce the soundcorresponding to the content selected by each user, toward the locationof each of the plurality of users which is recognized by the recognitionunit.

According to the invention, in the electronic device that displays aplurality of contents at the same time, the sound corresponding to thecontent selected by each user can be reproduced with respect to theuser.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-described objects, other objects, features and advantages willbe further apparent from the preferred embodiments described below, andthe accompanying drawings as follows.

FIG. 1 is a schematic view illustrating a method of operating anelectronic device according to a first embodiment.

FIG. 2 is a block diagram illustrating the electronic device shown inFIG. 1.

FIG. 3 is a plan view illustrating an oscillator shown in FIG. 2.

FIG. 4 is a cross-sectional view illustrating the oscillator shown inFIG. 3.

FIG. 5 is a cross-sectional view illustrating a piezoelectric vibratorshown in FIG. 4.

FIG. 6 is a flow chart illustrating a method of operating the electronicdevice shown in FIG. 1.

FIG. 7 is a block diagram illustrating an electronic device according toa second embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the invention will be described in detailwith reference to the accompanying drawings. Meanwhile, throughout thedrawings, like reference numerals refer to like elements, and thedescription thereof will not be repeated.

FIG. 1 is a schematic view illustrating a method of operating anelectronic device 100 according to a first embodiment. FIG. 2 is a blockdiagram illustrating the electronic device 100 shown in FIG. 1. Theelectronic device 100 includes a plurality of oscillators 10, a displayunit 40, a recognition unit 30, and a control unit 20. The electronicdevice 100 is, for example, a television, a display device in a digitalsignage, a portable terminal device, or the like.

The oscillators 10 output ultrasonic waves 16. The ultrasonic waves 16are modulation waves of a parametric speaker. The display unit 40displays a plurality of contents at the same time. The recognition unit30 recognizes the locations of a plurality of users. The control unit 20controls the oscillators 10 so as to reproduce sounds corresponding tothe contents. The control unit 20 controls the oscillators 10 so as toreproduce the sound corresponding to the content selected by each user,toward the location of each of the plurality of users which isrecognized by the recognition unit 30. Hereinafter, a configuration ofthe electronic device 100 will be described in detail with reference toFIGS. 1 to 5.

As shown in FIG. 1, the electronic device 100 further includes, forexample, a housing 90. As shown in FIG. 2, the oscillators 10, thecontrol unit 20, the recognition unit 30, and the display unit 40 aredisposed, for example, inside the housing 90.

The plurality of oscillators 10 are individually controlled, forexample, by the control unit 20. In addition, as shown in FIG. 2, theoscillator 10 can be constituted by a plurality of oscillators 12. Theplurality of oscillators 12 are individually controlled, for example, bythe control unit 20.

As shown in FIG. 1, the display unit 40 displays two contents at thesame time, for example, through two screens which are divided into rightand left portions. However, the displaying of the plurality of contentsusing the display unit 40 can also be modified in various ways, forexample, by a user's operation. Two contents can also be displayed atthe same time, for example, through two screens which are divided intoup and down portions, and four contents can also be displayed at thesame time through four screens.

The recognition unit 30 includes an imaging unit 32 and a determinationunit 34. The imaging unit 32 captures an image in a region including theplurality of users to generate image data. The determination unit 34determines the location of each user by processing the image data. Thedetermination of the location of each user is performed, for example, byindividually storing a feature amount for identifying each user inadvance, and by matching the feature amount and the image data. Thefeature amount can include, for example, the size of an interval betweenboth eyes of the user, and the size and shape of a triangle connectingboth eyes and a nose of the user. In addition, when the user moves in aregion where the imaging unit 32 captures an image, the recognition unit30 may have a function of determining the location of the user byautomatically following the user.

The control unit 20 is connected to the oscillators 10, the recognitionunit 30, and the display unit 40. The control unit 20 controls eachoscillator 10 so as to reproduce the sound corresponding to the contentselected by each user toward the location of each of the plurality ofusers, and this is performed, for example, as follows. First, thefeature amount of each user is registered in association with an ID.Next, the content selected by each user is associated with the ID ofeach user. Subsequently, an ID corresponding to a specific content isselected, and the feature amount associated with the selected ID is readout. A user having the read out feature amount is selected by imageprocessing, and the sound corresponding to the content is reproducedwith respect to the user.

FIG. 3 is a plan view illustrating the oscillator 10 shown in FIG. 2. Asshown in FIG. 3, the oscillator 10 is configured, for example, in such amanner that the plurality of oscillators 12 are arranged in an array.

FIG. 4 is a cross-sectional view illustrating the oscillator 12 shown inFIG. 2. The oscillator 12 includes a piezoelectric vibrator 60, avibration member 62, and a supporting member 64. The piezoelectricvibrator 60 is provided on one surface of the vibration member 62. Thesupporting member 64 supports an edge of the vibration member 62.

The control unit 20 is connected to the piezoelectric vibrator 60 via asignal reproduction unit 22. The signal reproduction unit 22 generatesan electrical signal to be input to the piezoelectric vibrator 60. Thecontrol unit 20 controls the signal reproduction unit 22 on the basis ofinformation that is input from the outside, thereby controlling theoscillation of the oscillator 12. The control unit 20 inputs amodulation signal as a parametric speaker via the signal reproductionunit 22. At this time, the piezoelectric vibrator 60 uses sound waves ofequal to or greater than 20 kHz, for example, 100 kHz, as carrier wavesof the signal.

FIG. 5 is a cross-sectional view illustrating the piezoelectric vibrator60 shown in FIG. 4. As shown in FIG. 4, the piezoelectric vibrator 60includes a piezoelectric body 70, an upper electrode 72, and a lowerelectrode 74. In addition, the piezoelectric vibrator 60 has, forexample, a circular shape or an oval shape. The piezoelectric body 70 isinterposed between the upper electrode 72 and the lower electrode 74. Inaddition, the piezoelectric body 70 is polarized in a thicknessdirection thereof. The piezoelectric body 70 is formed of a materialhaving a piezoelectric effect, for example, lead zirconate titanate(PZT) or barium titanate (BaTiO₃) as a material having a highelectro-mechanical conversion efficiency. In addition, the thickness ofthe piezoelectric body 70 may be preferably 10 μm to 1 mm. When thethickness is less than 10 μm, the piezoelectric body 70 is formed of abrittle material, and thus the piezoelectric body 70 is easily damagedduring the handling. On the other hand, when the thickness exceeds 1 mm,an electric field intensity of the piezoelectric body 70 decreases,thereby leading to a decrease in energy conversion efficiency.

The upper electrode 72 and the lower electrode 74 are formed of amaterial having electric conductivity, for example, silver or asilver/palladium alloy. Since silver is a low-resistance versatilematerial, there is an advantage from the viewpoint of a manufacturingcost and a manufacturing process. In addition, since a silver/palladiumalloy is a low-resistance material having an excellent oxidationresistance, it has an excellent reliability. The thicknesses of theupper electrode 72 and the lower electrode 74 are preferably 1 μm to 50μm. When the thicknesses are less than 1 μm, it is difficult touniformly form the upper electrode 72 and the lower electrode 74. On theother hand, when the thicknesses exceed 50 μm, the upper electrode 72 orthe lower electrode 74 serves as a constraint surface with respect tothe piezoelectric body 70, thereby leading to a decrease in energyconversion efficiency.

The vibration member 62 is formed of a material, such as a metal and aresin, having a high elastic modulus with respect to ceramic which is abrittle material, and is formed of a versatile material, for example,phosphor bronze or stainless steel. The thickness of the vibrationmember 62 is preferably 5 μm to 500 μm. In addition, a longitudinalelastic modulus of the vibration member 62 is preferably 1 GPa to 500GPa. When the longitudinal elastic modulus of the vibration member 62 isexcessively low or high, there is a concern that characteristics andreliability as a mechanical vibrator may be damaged.

In the embodiment, sound reproduction is performed using an operationprinciple of a parametric speaker. The operation principle of theparametric speaker is as follows. The sound reproduction is performedaccording to the operation principle of the parametric speaker thatemits ultrasonic waves on which an AM modulation, a DSB modulation, anSSB modulation, or a FM modulation is performed into the air, and issuesan audible sound based on the non-linear characteristics when ultrasonicwaves are propagated into the air. The term “non-linear” hereinindicates a transition from a laminar flow to a turbulent flow when theReynolds number expressed by the ratio of an inertial action and theviscous action of a flow increases. In other words, since the sound waveis very slightly disturbed within a fluid, the sound wave is propagatednon-linearly. In particular, when the ultrasonic waves are emitted intothe air, higher harmonic waves associated with the non-linearity areconspicuously generated. In addition, the sound wave is in a sparse anddense state in which molecular groups in the air are mixed in the lightand shade. When it takes more time for air molecules to be restoredrather than compressed, the air which is not capable of being restoredafter the compression collides with the continuously propagated airmolecules, and thus a shock wave occurs, thereby generating an audiblesound. Since the parametric speaker can form a sound field only around auser, there is an advantage from the viewpoint of privacy protection.

Hereinafter, a method of operating the electronic device 100 will bedescribed. FIG. 6 is a flow chart illustrating a method of operating theelectronic device 100 shown in FIG. 1. First, each user selects contentsthat he or she desires to view, and inputs the contents in theelectronic device 100 (S10). Next, the display unit 40 displays aplurality of contents selected by each user (S11). At this time, thedisplay unit 40 displays the plurality of contents at the same time.

Next, the recognition unit 30 recognizes the locations of a plurality ofusers (S12). The locations of the plurality of users are determined bythe determination unit 34 which processes the image data generated bythe imaging unit 32. The control unit 20 controls the oscillators 10 soas to reproduce the sound corresponding to the content selected by eachuser, toward the location of each of the plurality of users which isrecognized by the recognition unit 30 (S13). In the meantime, when therecognition unit 30 follows and recognizes the location of the user, thecontrol unit 20 may frequently control a direction in which theoscillator 10 reproduces the sound, on the basis of the location of theuser which is recognized by the recognition unit 30.

Hereinafter, effects of the embodiment will be described. According tothe electronic device 100 of the embodiment, sounds corresponding tocontents are reproduced by the ultrasonic waves 16 that are output bythe oscillators 10. The control unit 20 controls the oscillators 10 soas to reproduce the sound corresponding to the content selected by eachuser, toward the location of each of the plurality of users. Since thesounds corresponding to the contents are reproduced by ultrasonic waveshaving a high directionality, the plurality of sounds corresponding tothe contents are not mixed together. Accordingly, in the electronicdevice that displays the plurality of contents at the same time, thesound corresponding to the content selected by each user can bereproduced with respect to the user.

FIG. 7 is a block diagram illustrating an electronic device 102according to a second embodiment and corresponds to FIG. 2 according tothe first embodiment. The electronic device 102 according to theembodiment is the same as the electronic device 100 according to thefirst embodiment except that the electronic device 102 includes aplurality of detection terminals 50.

The plurality of detection terminals 50 are respectively held by aplurality of users. The recognition unit 30 recognizes the locations ofthe users by recognizing the locations of the detection terminals 50.The recognition of the locations of the detection terminals 50 using therecognition unit 30 is performed, for example, by causing therecognition unit 30 to receive electric waves emitted from the detectionterminals 50. In addition, when the user holding the detection terminal50 moves, the recognition unit 30 may have a function of determining thelocation of the user by automatically following the user. The detectionterminal 50 may have, for example, a function of selecting contents anda function of adjusting a volume of a sound reproduced by the ultrasonicwaves 16.

In addition, the recognition unit 30 may include the imaging unit 32 andthe determination unit 34. The imaging unit 32 generates image dataobtained by capturing an image in a region including the user, and thedetermination unit 34 processes the image data, thereby allowing thedetailed location of the ear or the like of the user to be specified.For this reason, the location of the user can be further preciselyrecognized in conjunction with the location detection using thedetection terminals 50.

Even in the embodiment, the control unit 20 controls each oscillator 10so as to reproduce the sound corresponding to the content selected byeach user toward the location of each of the plurality of users, andthis is performed, for example, as follows. First, an ID of eachdetection terminal 50 is registered in advance. Next, the contentselected by each user is associated with the ID of the detectionterminal 50 held by each user. Subsequently, the ID indicating eachdetection terminal 50 is transmitted from the detection terminal 50. Therecognition unit 30 recognizes the location of the detection terminal 50on the basis of a direction in which the ID is transmitted. Then, thesound corresponding to a specific content is reproduced to the userholding the detection terminal 50 having an ID corresponding to thecontent.

In addition, when each user operates his or her own detection terminal50 to select the content, the sound corresponding to the content may bereproduced toward the user having the detection terminal 50.

Even in the embodiment, the same effects as the first embodiment can beobtained.

As described above, although the embodiments of the invention have beenset forth with reference to the drawings, these are merely illustrativeof the invention, and various configurations other than those statedabove can be adopted.

The application is based on Japanese Patent Application No. 2011-020032filed on Feb. 1, 2011, the content of which is incorporated herein byreference.

1. An electronic device comprising: a plurality of oscillators thatoutput modulation waves of a parametric speaker; a display unit thatdisplays a plurality of contents at the same time; a recognition unitthat recognizes the locations of a plurality of users; and a controlunit that controls the oscillators so as to reproduce soundscorresponding to the contents, wherein the control unit controls theoscillators so as to reproduce the sound corresponding to the contentselected by each user, toward the location of each of the plurality ofusers which is recognized by the recognition unit.
 2. The electronicdevice according to claim 1, further comprising: a plurality ofdetection terminals that are respectively held by the plurality ofusers, wherein the recognition unit recognizes the locations of theusers by recognizing the locations of the detection terminals.
 3. Theelectronic device according to claim 1, wherein the recognition unitincludes: an imaging unit that generates image data by capturing animage in a region including the user; and a determination unit thatdetermines the location of the user by processing the image data.
 4. Theelectronic device according to claim 1, wherein the recognition unitfollows and recognizes the location of the user, and wherein the controlunit frequently controls a direction in which the oscillator reproducesthe sound, on the basis of the location of the user which is recognizedby the recognition unit.
 5. The electronic device according to claim 1,wherein the electronic device is a portable terminal device.